Compound interest
Use A = P(1 + r)^n to find the future value or interest earned on a compound-interest investment. Unlimited questions, five difficulty levels, and a full worked solution every time — free.
Try one
Aisha invests $200.00 at 6%/year, compounded annually, for 1 year. To the nearest cent, how much interest will the investment earn?
Answer: 12
See one solved, step by step
Layla invests $1300.00 at 4.5%/year, compounded annually, for 4 years. To the nearest cent, how much interest will the investment earn?
📘 Worked solution
1A = P(1 + r)n = 1300(1 + 0.045)4Compound interest formula, using the periodic rate as a decimal.
2A = 1550.27Evaluate the power, then multiply by the principal.
3I = A - P = 1550.27 - 1300 = 250.27Interest earned is the final amount minus the original principal.
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